In-line production of linerless labels

ABSTRACT

According to an embodiment of the present disclosure, a method of labeling a plurality of products includes coating a pressure sensitive adhesive to a roll of face stock, the roll of face stock configured to be converted to a plurality of individual labels aligned in a single lane; singulating an individual label from the roll of face stock; and applying the individual label to a product of the plurality of products, wherein the coating, singulating and applying are conducted sequentially in a single continuous operation with a single continuous web of material.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/687,429 filed in the USPTO on Aug. 25, 2017, which claims priority toU.S. Provisional Patent Application No. 62/460,873, filed Feb. 20, 2017,the entire content of which is incorporated herein by reference.

FIELD

The following description relates generally to linerless pressuresensitive adhesive labels, and method and system of manufacturing thesame.

BACKGROUND

A related art pressure sensitive adhesive (PSA) label stock has amulti-layer laminated structure including four necessary elements: aface or face-stock, an adhesive layer, a release system and a liner.This label stock, which is commonly produced in roll form includingmultiple individual labels, is converted into individual labels. Anend-user may then apply an individual label to a product. The residualliner, coated with the release system, becomes a waste stream. Thiswaste stream is collected on a rewind stand following dispensing (i.e.,the application of labels) and may subsequently be land-filled or soldinto low value reprocessing.

To reduce the waste generated through the labeling process, the labelingindustry has sought to find ways to affect labeling of PSA-typematerials without utilizing a liner and the associated release system,thus significantly improving material and supply chain efficiencies,reducing cost and eliminating an increasingly problematic waste stream.Only limited progress has been made to achieving this goal, commonly inthe form of so-called “liner-free” labels and “activatable” labels.

The liner-free labels are typically manufactured by first printing oneside of the face stock with an indicia and then applying a releasesystem to the same side of the printed face stock before coating thereverse side of the face stock with an adhesive to create a self-woundlabel stock that does not include the liner. While the liner has beeneliminated, the release system is still coated on the face-stock, andtherefore does not deliver the full cost potential of a true linerlesssolution.

Activatable labels, on the other hand, involve applying a specialtycoating or cover layer to the adhesive system (essentially replacing theliner and the release system) or having an adhesive system which isnon-tacky at room temperature. In these solutions a separate process,just prior to labeling, either removes the coating/cover layer to“unmask” the adhesive or activates the adhesives through an externalstimulus such as heat or liquid. While the activatable labels do indeedeliminate the liner and the release system, and, therefore, a wastestream, they replace them with another, often relatively expensivematerial, add complexity and may not improve cost significantly. Bothliner-free and activatable label approaches have found limitedcommercial utility.

There remains a need for a true linerless solution that eliminates boththe liner and the release system, and does not replace either withanother component.

SUMMARY

An aspect according to one or more embodiments of the present inventionis directed toward a method of labeling a plurality of products, thelabels are free of any liner and any release system and are not replacedwith any other material.

Another aspect according to one or more embodiments of the presentinvention is directed toward a system of labeling a plurality ofproducts, the labels are free of any liner and any release system andare not replaced with any other material.

Additional aspects will be set forth in part in the description whichfollows, and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to an embodiment of the present disclosure, a method oflabeling a plurality of products is provided. The method includescoating a pressure sensitive adhesive to a roll of face stock, the rollof face stock configured to be converted to a plurality of individuallabels aligned in a single lane; singulating an individual label fromthe roll of face stock; and applying the individual label to a productof the plurality of products, wherein the coating, singulating andapplying are conducted sequentially in a single continuous operationwith a single continuous web of material.

In one embodiment, no winding or rewinding of the roll of face stock isconducted between the coating of the pressure sensitive adhesive, thesingulating and the applying of the individual label.

In one embodiment, the method may further include weakening the roll offace stock to enable singulating of individual labels. The weakening ofthe roll of face stock may be conducted prior to the coating of thepressure sensitive adhesive and including perforating or weakening aborderline of an individual label.

In one embodiment, the weakening of the roll of face stock may beconducted after the coating of the pressure sensitive adhesive and priorto the singulating of the individual label, and including cutting alonga borderline of an individual label utilizing a laser, a cutting die,and/or a knife.

In one embodiment, the method may further include printing an indicia onthe face stock. The printing may be conducted prior to the coating ofthe pressure sensitive adhesive at a site different from a site for thecoating of the pressure sensitive adhesive.

In one embodiment, the printing may be conducted prior to the coating ofthe pressure sensitive adhesive at a same site as a site for the coatingof the pressure sensitive adhesive and may be conducted sequentiallywith the coating, singulating and applying.

The roll of face stock may have a first indicia prior to the printing,and the printing may provide a second indicia to the roll of face stock.

The pressure sensitive adhesive may have a coat weight of about 3 gsm toabout 20 gsm.

The pressure sensitive adhesive may have a 180° peel of about 1 N/inchto about 20 N/inch.

In one embodiment, the method may further include unwinding the roll offace stock prior to the coating of the pressure sensitive adhesive,wherein a total time needed from unwinding a section of the face stockcorresponding to an individual label to a completion of the applying ofthe individual label to a product is about 60 seconds or less.

In one embodiment, the method may further include curing the pressuresensitive adhesive after the coating of the pressure sensitive adhesiveand prior to the singulating of the individual label.

The curing may be through a radiation source with a dosage of about 2mJ/cm² to about 50 mJ/cm².

The coating may be conducted at a temperature of about 60° C. to about170° C.

In one embodiment, the applying of the individual label may be about 10seconds or less after the coating of the pressure sensitive adhesive.

The coating of the pressure sensitive adhesive may be through diecoating, screen coating, and/or spray coating.

According to an embodiment of the present disclosure, a system to labela plurality of products is provided. The system includes a coatingstation to coat a pressure sensitive adhesive to a roll of face stock,the roll of face stock configured to be converted to a plurality ofindividual labels aligned in a single lane; a singulating station tosingulate an individual label from the roll of face stock; and adispensing station to apply the individual label to a product of theplurality of products, wherein the coating station, the singulatingstation and dispensing station are located at a same site to providesequential coating of the pressure sensitive adhesive, singulating ofthe individual label and applying of the individual label.

In one embodiment, the system may further include a transportationstation to move the face stock from an unwinding station to the coatingstation, the singulating station and the dispensing stationsequentially.

The transportation station may include a belt.

In one embodiment, the system may further include a weakening station tocreate separation between adjacent individual labels.

In one embodiment, the system may further include an accumulationstation between the coating station and the singulating station toaccumulate the coated face stock when a speed of the face stock at thecoating station is faster than a speed of the face stock at thesingulating station.

In In one embodiment, the system may further include an (inetermdiate)transportation system and accumulation station between the coatingstation and the singulating station to accumulate the coated face stockwhen a speed of the face stock at the coating station is faster than aspeed of the face stock at the singulating station.

In one embodiment, the system may further include a printing station toprint an indicia on the face stock.

According to an embodiment of the present disclosure, a pressuresensitive adhesive label consists of a face stock; an indicia on theface stock; and a pressure sensitive adhesive on the face stock, whereinthe pressure sensitive adhesive has a coat weight of about 3 gsm toabout 20 gsm, and a 180° peel of about 1 N/inch to about 20 N/inch.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will bebetter understood by reference to the following detailed descriptionwhen considered in conjunction with the accompanying drawings. It isunderstood that selected structures and features have not been shown incertain drawings so as to provide better viewing of the remainingstructures and features.

FIG. 1 is a schematic illustration of a method of labeling a pluralityof products.

FIG. 2 is a schematic illustration of a section of a roll of face stock.

FIG. 3 is a schematic illustration of a process of labeling a pluralityof products according to an embodiment of the present disclosure.

FIG. 4 is a schematic illustration of a face stock with adhesive coatedin lanes.

FIG. 5A and 5B are schematic illustrations of a label face stock with amatrix.

FIG. 6 is a schematic illustration of a labeling process according to anembodiment of the present disclosure.

FIG. 7 is a schematic illustration of an example labeling process at theclient's site.

FIG. 8 is a schematic illustration of a process including the inlineprinting.

FIG. 9 is a schematic illustration of a labeling process.

FIG. 10 is a schematic illustration of a labeling process.

DETAILED DESCRIPTION

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting of theinvention. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

Expressions such as “at least one of” or “at least one selected from”when preceding a list of elements, modify the entire list of elementsand do not modify the individual elements of the list. Further, the useof “may” when describing embodiments of the present invention refers to“one or more embodiments of the present invention.”

It will be understood that when an element or layer is referred to asbeing “on”, “connected to”, “coupled to”, or “adjacent to” anotherelement or layer, it can be directly on, connected to, coupled to, oradjacent to the other element or layer, or one or more interveningelements or layers may be present. In contrast, when an element or layeris referred to as being “directly on,” “directly connected to”,“directly coupled to”, or “immediately adjacent to” another element orlayer, there are no intervening elements or layers present.

As used herein, the terms “substantially,” “about,” and similar termsare used as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art. Also, any numerical range recited herein is intended to includeall sub-ranges of the same numerical precision subsumed within therecited range. For example, a range of “1.0 to 10.0” is intended toinclude all subranges between (and including) the recited minimum valueof 1.0 and the recited maximum value of 10.0, that is, having a minimumvalue equal to or greater than 1.0 and a maximum value equal to or lessthan 10.0, such as, for example, 2.4 to 7.6. Any maximum numericallimitation recited herein is intended to include all lower numericallimitations subsumed therein and any minimum numerical limitationrecited in this specification is intended to include all highernumerical limitations subsumed therein. Accordingly, Applicant reservesthe right to amend this specification, including the claims, toexpressly recite any sub-range subsumed within the ranges expresslyrecited herein.

According to an embodiment of the present disclosure, a method oflabeling a plurality of products is provided. The method includescoating a pressure sensitive adhesive to a roll of face stock, the rollof face stock configured to be converted to a plurality of individuallabels aligned in a single lane; singulating an individual label fromthe roll of face stock; and applying the individual label to a productof the plurality of products, wherein the coating, singulating andapplying are conducted sequentially in a single continuous operationwith a single continuous web of material. Here, “a single continuousoperation” refers to the process where the coating, singulating andapplying onto a product is conducted on a given portion of the roll offace stock (i.e., a given portion of the web of material) in the samemanufacturing line (e.g., labeling line) sequentially. The roll of facestock is continuously unwound from an unwinding station at the beginningof the manufacturing line, is transported through the coating stationand other stations (e.g., a curing station) if applicable, and iscontinuously singulated into individual labels and applied onto theproducts at the end of the manufacturing line. The process may includevariable speed (e.g., different speed at different stations) but shouldnot include winding up the entire roll of face stock and unwinding itagain at a different time and/or a different location between thecoating station and the singulating and applying stations.

According to an embodiment of the present disclosure, no winding orrewinding of the roll of face stock is conducted between the coating ofthe pressure sensitive adhesive, the singulating and the applying of theindividual label. For example, the coating, singulating and applying maybe conducted sequentially and continuously in time in the same process.Here, the adhesive coated face stock with indicia printed thereon formsa label, and the adhesive coated roll of face stock with indicia printedthereon becomes a roll of label stock, which may include a plurality ofindividual labels.

FIG. 1 is a schematic illustration of a method of labeling a pluralityof products. Referring to FIG. 1, a roll of face stock 101 is unwound ata station 110. The face stock 101 passes through a coating station 120and a layer of pressure sensitive adhesive 103 is coated on the facestock 101. In one embodiment, the face stock 101 passes through a curingstation 130 to produce a cured pressure sensitive adhesive 105. Inanother embodiment, the curing station 130 is not included in thelabeling process and the pressure sensitive adhesive is not cured.

The face stock 101 then passes through a singulating station 140 and anindividual label 107 at the leading edge of the face stock is singulated(i.e., picked out) of the roll of face stock 101. Next, at thedispensing station 150, the individual label 107 is applied onto aproduct 109 from a plurality of products. While the singulating andapplying of the individual label are described as being conductedrespectively at the singulating station 140 and the dispensing station150, embodiments of the present disclosure are not limited thereto, andthe singulating and applying of the individual label may both beconducted at the dispensing station, for example, by a same tool thatpicks out an individual label and applies that label to a product and/oras part of a single process.

As the labeled product 109 is moved away from the dispensing station, anext individual label is applied to a next product, and the process oflabeling is conducted continuously. In one embodiment, a time span fromthe beginning of the coating of the PSA to the completion of thedispensing of the individual label is 60 seconds or less for eachindividual label. FIG. 9 is a schematic illustration of a labelingprocess. Referring to FIG. 9, according to an embodiment, it takes lessthan 60 seconds for an individual label from the roll of face stock(e.g., a printed roll of film or paper) to travel from the unwindingstation to the completion of the applying of the label. In anotherembodiment, it takes less than 30 seconds for an individual label fromthe roll of face stock (e.g., a printed roll of film or paper) to travelfrom the unwinding station to the completion of the applying of thelabel.

The face stock may be made of any suitable material. For example, theface stock may be paper based or film based (e.g., made of clear plasticmaterial, opaque plastic material, foil, metalized paper, metalizedfilm, laminate, etc.). In one embodiment, the face stock may have athickness of about 20 microns or less, for example, about 10 microns orless, or about 8 microns.

The roll of face stock may be converted to a plurality of, for example,500, 1000, 2000. 10,000 or more, of individual labels. Accordingly, theroll of face stock may be weakened to create separation between adjacentindividual labels. The weakening of the roll of face stock may beconducted prior to the coating of the pressure sensitive adhesive andmay include perforating or weakening a borderline of each individuallabel.

In one embodiment, the weakening of the roll of face stock may beconducted at a site different from the site where the labeling isconducted. For example, the weakening of the roll of face stock may beconducted at a manufacturing site where the roll of face stock is, forexample, printed. When the roll of face stock reaches the unwindingstation 110, the weakening has already been completed and a perforatedline or a weakened line has been created between neighboring individuallabels to define each individual label while the labels are stillconnected to one another. Hereinafter, the term “weakened” refers to thestate of the label web (e.g., the roll of face stock) where individuallabels can be easily separated from the web yet are still connected tothe web. The weakened line may be the perforated line or a cutting linethat cuts through only a portion of the web along the thicknessdirection. Throughout this description, the terms “web” and “roll” areused interchangeably.

In one embodiment, the weakening of the roll of face stock may beconducted after the coating of the pressure sensitive adhesive and priorto the singulating of the individual label, and may include cuttingalong a borderline of an individual label utilizing a laser beam, acutting die, or a knife. While example weakening methods have beendescribed, embodiments of the present disclosure are not limited theretoand any suitable weakening methods may be utilized.

FIG. 2 is a schematic illustration of a section of a roll of face stock.Referring to FIG. 2, the roll of face stock 101 includes a plurality ofindividual labels 101 a aligned in a single lane. The individual labelsmay have a perforation line or a weakened line 101 b around it'scircumference, but embodiments of the present disclosure are not limitedthereto, and the roll of face stock may not include the perforation lineor weakened line 101 b.

The face stock 101 may include an indicia printed on a surface thereof.In one embodiment, the printing may be conducted prior to the coating ofthe pressure sensitive adhesive at a site different from the site forthe coating of the pressure sensitive adhesive. The printing process maynot be part of same continuous labeling process described in associationwith FIG. 1.

The printing may be conducted at a label manufacturing site where thelabel face stock is printed and wound into the roll. The indicia maydescribe and advertise for the product to be labeled. For example, theindicia may be the product name, information about the product, a logoassociated with the product, etc. This printing may be conducted on acontinuous (roll-to-roll) press producing many labels across and downthe web of the label stock. The web of the label stock may be slit intosingle lane labels prior to the labeling process described inassociation with FIG. 1.

In one embodiment, the printing may be conducted prior to the coating ofthe pressure sensitive adhesive at the same site as the site for thecoating of the pressure sensitive adhesive and may be conducted in thesame process, e.g., sequentially and/or continuously in time, with thecoating, singulating and applying. FIG. 3 is a schematic illustration ofa process of labeling a plurality of products according to an embodimentof the present disclosure. In FIG. 3, the same reference numerals areutilized as in FIG. 1 to indicate similar process and materials, and thedescription thereof is not repeated again.

Referring to FIG. 3, a roll of face stock 101 including a plurality oflabels 101 a is unwound at the unwinding station 110. The face stock 101passes through a printing station 170 first and a second indicia isprinted on the face stock 101. Here, the roll of face stock 101 may havea first indicia printed at the manufacturing site, and the secondindicia may add, for example, customized information to the labels 101a. In one embodiment, the roll of face stock 101 may not include thefirst indicia and the entire printing is conducted in-line at theprinting station 170. The printing may be on either side of the facestock or on both sides (with the use of two printing stations).

The pressure sensitive adhesives may be either a hot melt PSA or a warmmelt PSA. Any suitable pressure sensitive adhesive formulation thatsatisfies the following conditions may be utilized: forms a clearpressure sensitive adhesive layer, flows well to form a high qualitycoating (e.g., uniform coating without significant defects) at low coatweights, can be coated at temperatures ranging from about 60° C. to 170°C., and requires limited or no post-coating processing. For the purposeof the current description, the term “hot melt adhesive” or “hot meltpressure sensitive adhesive” refers to a pressure sensitive materialthat flows and is coatable to give a high quality coating attemperatures of about 110° C. and above. The term “warm melts” or “warmmelt pressure sensitive adhesive” refers to a pressure sensitivematerial that flows and is coatable to provide a high quality coating attemperatures from about 60° C. to about 110° C. The coating may beconducted at a temperature of about 60° C. to about 170° C.

Suitable pressure sensitive adhesives may be based on acrylic polymers,rubber based polymers such as block, tapered or random copolymers ofstyrene, butadiene, isoprene, or ethylene butylene, polyurethanes,silicone polymers or hybrids (graft or block or random copolymers of theabove polymers), or combinations or blends of the above mentionedpolymers with or without further additives. These polymers or copolymerscan be random, block, or graft copolymers.

The polymers may be further modified with a wide range of additives.Non-limiting example additives include tackifiers, plasticizers,fillers, crosslinkers, viscosity modifiers, etc., which are eithercommercially available or custom synthesized. The additives may havevery low vapor pressure at the coating temperature and may not emitingredients that are harmful or odorous. Other suitable additives thatmay be utilized are those to enhance adhesion to wet bottles, or thosethat enhance adhesion under wet conditions.

The glass transition temperature (Tg) of the suitable pressure sensitiveadhesives is typically about 20 to 25° C. below the usage/applicationtemperature. For example, for room temperature applications, the PSA mayhave a Tg of lower than about 0° C.

Suitable pressure sensitive adhesives may be readily coated utilizingdie coating, screen coating, spraying or other suitable coatingtechnologies at temperatures which do not distort or affect theaesthetics of the face stock material upon which they are coated. Theviscosities of the adhesive at the coating temperature should besuitable for forming a high quality coating on the web. For example, theviscosity of the adhesive may range from about 100 centipoise to about15,000 centipoise or even higher at the coating temperature.

The molecular weight of the polymers may be any suitable value as longas once formulated with the additives, the viscosity of the adhesivecomposition falls in the range of interest to form a high qualitycoating at the coating temperature. For example, the weight averagemolecular weight may be about 20,000 Daltons to about 300,000 Daltons.

When a filmic face stock (e.g., face stock made of a polymer material)is utilized for the labels, it is typically sensitive to hightemperatures. For such face stocks, a ultraviolet (UV) curable warm meltadhesive or a warm melt adhesive that does not require any curing may beutilized. The warm melt adhesive may be applied to the filmic web (i.e.,filmic face stock web) at relatively lower temperatures (e.g., belowabout 130° C.) without distorting the web.

The coating temperature may be further lowered by dissolving the hotmelt adhesive or warm melt adhesive in a low vapor pressure, highboiling point, benign co-monomer or low molecular weight polymeradditive to make a syrup, coating the syrup on the web and curing it.The usage of a syrup further enhances the coating quality and alsoallows the usage of more heat sensitive filmic label face stocks such aspolyethylene (PE).

The UV curable adhesive system (adhesive formulation), for example, maybe based on either acrylic or rubber based chemistries. Non-limitingexamples of suitable UV curable adhesives include those from supplierssuch as BASF, Henkel, or others. The hot melt adhesives may be readilyand robustly coated at low coat weights. In one embodiment, the coatweight is in the range of about 3 gsm to about 20 gsm, or in the rangeof about 3 gsm to about 12 gsm, depending on the face stock. Theadhesive may be coated utilizing any suitable coating technology.

In one embodiment, a hot melt adhesive is metered via a pump from astandard tank to a small slot die coater. The slot die coater can beobtained from any of a number of companies such as Acumeter, ITW,Nordson, etc. A slot die with a smoothing rod will ensure a high qualitycoating at the low coat weights. At the coating head the adhesive isapplied to the reverse side of the printed and weakened face material(i.e., the adhesive is applied to a side opposite to the side where theindicia is printed on the face material) which is fed continuously intothe die. The coating width may be easily adjusted utilizing shims on thedie to match the width of the face stock web.

In one embodiment, the method may further include curing the pressuresensitive adhesive after the coating of the pressure sensitive adhesiveand prior to the singulating of the individual label. The curing may bethrough a radiation source with a dosage of about 2 mJ/cm² to about 50mJ/cm².

For example, after the hot or warm melt adhesive is applied to the labelface stock, the face stock exits the die. Optionally, the adhesive isexposed to a short burst of UV radiation at a curing station (forexample, at a dosage ranging from about 5 mJ/cm² to about 50 mJ/cm²)which partially cures the adhesive and readies it to be applied directlyto products at the singulating station.

In one embodiment, the post-coating unit (e.g., at the curing station)is compact and robust. A curing unit from a company such as Nordson,Dymax, Fusion etc., may be utilized for the curing. The radiation neededto cure may depend on the adhesive utilized and typically low dosagesare adequate for these labels. For example, a lamp (such as a D bulbfrom Fusion) with an output of 500 watt/in or less may be utilized toeffect the cure at a high speed and a short time.

The type of lamp utilized determines the wavelength of the radiation andmay be selected according to the adhesive utilized. For example, theBASF AC 250 adhesive with the low coat weight described above may becured utilizing a lamp with a UV-C radiation at a wavelength of 250 nmto 290 nm and at dosage of about 2 to 50 mJ/cm². Lamps in a unit that is6″ wide and 8″ long have been utilized after the web exits the die. Theadhesive passes under the lamps and is exposed to a continuous burst ofUV for a short period of time.

For clear filmic label face stock materials utilized for clear-on-clearapplications, where the appearance of the final label on the productrequires the adhesive to be uniform, clear and defect free, utilizing acontinuous coating of a UV curable hot melt or warm melt adhesive hasbeen found to be effective.

For paper based labels and opaque filmic labels, where the adhesivecannot be seen after the label is applied onto the product, the coatingmethods may be selected to further provide cost advantages. In oneembodiment, the hot melt adhesive is sprayed onto the printed webutilizing standard hot melt spray nozzles. Coating the adhesive by thespraying method may reduce the total amount of adhesive required, as itis not a continuous covering and it also does not require the contact ofthe coating system with the web (therefore reducing the web tensionrequired to pull the web through the coating system to the singulatingstation). After spraying, the adhesive may be cured by UV radiation, ifneeded, as it passes under the lamps in the curing unit. The sprayingcan be done using a system such as a Universal Spray Nozzle system byNordson.

In another embodiment, a standard die is deckled so as to coat the hotmelt adhesive in lanes. This provides for a discontinuous coating andthereby reduces the amount of adhesive utilized. FIG. 4 is a schematicillustration of a face stock with adhesive coated in lanes. Referring toFIG. 4, adhesive 103 is coated on the face stock 101 in the shape ofstrips with each strip spaced apart from neighboring strips.

In another embodiment, the adhesive may be printed (e.g., with adiscontinuous pattern) on to the web utilizing, for example, a Storkscreen printer.

The pressure sensitive adhesives according to embodiments of the presentdisclosure are chosen to meet the Dahlquist criteria, and more detailson the types of PSA materials that can be utilized can be found in awide range of patents and publications, one such being the Handbook ofPressure Sensitive Adhesive Technology, Second Edition, Ed. DonatasSatas, van Nostrand Reinhold, NY, 1989, the entire content of which isincorporated herein by reference.

The pressure sensitive adhesive may have a 180° peel on a glass panel ofabout 1 N/inch to about 20 N/inch, for example, of about 5 N/inch toabout 17 N/inch.

In one embodiment, no curing or drying is conducted after the coating ofthe adhesive, i.e., the adhesive coated on the label face stock does notrequire any curing or drying.

After the label face stock has been adhesive coated and optionallycured, it may be pulled through to the singulating station 140. At thesingulating station 140, labels are removed from the web, singulated,and applied continuously to products that are presented to thedispensing station for continuous application to products. Singluationmay occur by effectively tearing the label from a pre-weakened web orvia die cutting utilizing, for example, a knife or die cutting tool.

The web may be pulled through to the singulating station (from thestarting unwinding station 110 and through the coating station 120)utilizing, for example, a low surface energy belt (which contacts theadhesive side of the web), a friction belt (which contacts the printedside of the web) or a winder (which collects any matrix remaining afterthe labels have been removed from the web).

When a winder is utilized to pull the web, leaving a small (e.g., about⅛″) lane on either side of the labels may provide a sufficient matrix toallow a rewind station to pull the label stock through the entireprocess. FIG. 5A and 5B are schematic illustrations of a label facestock with a matrix. Referring to FIG. 5A, a label face stock 101includes the labels 101 a and a matrix 101 c at both sides of the labels101 a. The matrix 101 c may have a width (from the edge of the label 101a to the corresponding edge of the face stock 101) of about 1/10″ toabout ½″ (and could vary in width for labels which do not have squarecorners). Referring to FIG. 5B, after the label 101 a has been pickedout of the web and applied to the product, only the matrix 101 c remainsand it is rewound at the rewind station.

The usage of a winder after the dispensing station, which is common inrelated art labeling process (for collecting the matrix and pulling thelabel stock through the dispensing system) may be suitable for applyinglabels which are not rectangular or square shaped. For the irregularlyshaped labels, there is often material left in the web (described hereas the matrix) after singulation of the labels and this matrix can bereadily collected on a winder. The winder may be utilized in conjunctionwith the belt or without the belt.

FIG. 6 is a schematic illustration of a labeling process according to anembodiment of the present disclosure. In FIG. 6, the same referencenumerals are utilized as in FIG. 1 to indicate similar process andmaterials, and the description thereof is not repeated again.

Referring to FIG. 6, a roll of face stock 101 including a plurality oflabels 101 a is unwound at unwinding station 110. The face stock 101passes through a coating station 120 and an adhesive layer 103 is coatedon the face stock 101. The adhesive may be optionally cured. The web maybe optionally rotated 90° and reaches the singulating station 140. Afterthe individual label 107 is singulated (i.e., picked out of the web) andapplied onto the product 109, the left over matrix 111 is wound up atthe winding station 160.

In one embodiment, the applying of the individual label may be about 10seconds or less, for example, about 6 seconds or less, after the coatingof the pressure sensitive adhesive. In one embodiment, the labelingprocess may be conducted at a rate of about 50 labels/min to about 1000labels/min.

According to an embodiment of the present disclosure, a system forlabeling a plurality of products is provided. The system includes acoating station to coat a pressure sensitive adhesive to a roll of facestock, the face stock including a plurality of individual labels alignedin a single lane; a singulating station to singulate an individual labelfrom the roll of face stock; and a dispensing station to apply theindividual label to a product of the plurality of products, wherein thecoating station, the singulating station and dispensing station arelocated at a same site to provide continuous coating of the pressuresensitive adhesive, singulating of the individual label and applying ofthe individual label.

In one embodiment, the system may further include a transportationstation for moving the face stock from an unwinding station to thecoating station, the singulating station and the dispensing stationsequentially. The transportation station may include a belt, e.g., aconveyer belt.

When singulation is enabled by cutting the individual labels in-line atthe singulating station (or dispensing station if no separatesingulating station is utilized), the web speed may vary at the point ofdispensing. For example, the web may slow down or briefly stop tocomplete the cutting. This will lead a different web speed at thesingulating station and at the coating station. To reduce or eliminateany coating defects that the web speed variation may cause, anaccumulator may be utilized after the coating station, which may providea method of maintaining a constant web speed through the coating stationwhilst removing slackness in the web caused by the web speed variationsdownstream. In another embodiment, a driven roller (or belt) may beincluded between the coating station and the accumulator, which mayensure that the web speed remains constant through the coating station.Similarly in some embodiments, the application of the singulated labelto product may require a variable speed and again an accumulator may beutilized to ensure that the web speed at the coating station isconstant.

In one embodiment, the system may further include an accumulationstation between the coating station and the singulating station toaccumulate the face stock when the speed of the face stock at thecoating station is faster than the speed of the face stock at thesingulating station. For example, the system may include twotransportation stations. A first station (e.g., a belt driven by a firstroller) to move the face stock through the coating station at a firstconstant speed, and then a second station (or system) (e.g., a beltdriven by a second roller) which moves the coated face stock through thesingulating and dispensing stations at a second constant speed or avariable speed. The first and second constant speeds may be of differentvalues at any moment in time (although the time-averaged speeds will bethe same). The two transportation stations provide for a continuous webspeed through the coating station and allow for a variable web speedthrough the singulating and dispensing stations. The accumulation couldalso be conducted in the form of a larger roll or a belt onto which thesingulated labels are dispensed and further decoration of the objectscan be done from this dispensing accumulation roll. This enables thecoating to be done in a continuous manner.

In one embodiment, the system may further include a weakening station tocreate separation between adjacent individual labels. In one embodiment,the system may further include a printing station for printing anindicia on the face stock.

The labeling system according to embodiments of the present disclosureenables the elimination of both the liner and the release layer, anddoes not replace either with another component. It thereby delivers onthe true cost and environmental promise of a linerless solution. Thereis additional complexity at the point of dispensing but this complexityis readily justified by the substantial savings, environmental benefits,and supply chain efficiencies offered by the invention. Further,according to an embodiment of the present disclosure, the face stock mayhave a thickness of about 20 microns or less. In related art labelingprocess, the usage of face materials below 25 microns is rare becausedie-cutting only the face stock and the adhesive layers over the releasesystem and the liner becomes difficult at low thickness without damagingthe liner and thereby the integrity of the total roll. The adhesive coatweight may be about 3 gsm to about 20 gsm, for example, less than 10gsm, which is much lower than that used in a related art label andrelated art labeling system (which is typically greater than 15 gsm).

According to an embodiment of the present disclosure, an example labelmanufacturing process begins at the label manufacturing site, where aroll of face stock material (paper or film) is first printed, as is donetoday with related art labeling, with information and advertising thatwill be placed on the products to be labeled. During the same process,but after the printing, the face stock is perforated or weakened,utilizing, for example, a rotating die, to create a roll of printedmaterial with individual labels defined by weakened areas at theextremities of each label. The roll of printed face stock, which carriesthe ‘weakened’ labels, is then slit to provide a single lane of labels.The printing and the slitting processes are substantially the same asthe corresponding related art ones, except that the label face stocksare only weakened and not die cut through the entire label face stock.

The slit roll is then shipped off the manufacturing site and provided tothe end user at the labeling site. In the subsequent labeling process,the roll is fed into a coating station which applies a thin (3gsm to 15gsm) coating of a hot melt or a warm melt PSA (which could optionally beUV curable) to the face stock material. If it is a UV curable adhesive,it may be rapidly and partially (or completely) cured by a low dose ofUV as it exits the coating station and is then fed directly to thesingulating station. However, with choice of the right hot melt or warmmelt adhesive (with the desired adhesion performance), no curing isnecessary. In one embodiment, after the coating of the adhesive, nodrying is needed. The adhesive coated face stock is directly passed onto the singulating station without any drying process. In anotherembodiment, after the coating of the adhesive, no drying and no curingare conducted. The adhesive coated face stock is directly passed on tothe singulating station without any drying or curing process.

At the singulating station and the dispensing station (or a combineddispensing station without a separate singulating station), the labelsare singulated by breaking the lines of weakness, which were createdduring the printing process at the manufacturing site, and are thenapplied to products in a continuous fashion.

While specific process steps are described in association with theexample process above, embodiments of the present disclosure are notlimited thereto. For example, the face stock material may not beperforated at the manufacturing site, an adhesive other than UV curablehot melt or warm melt adhesives may be utilized, other suitableenergy-activated, rapidly curable adhesives or non-curable adhesives maybe utilized, and/or part or all of the printing may be done during thelabeling process. While a label face stock with a plurality ofindividual labels aligned in a single lane has been described,embodiments of the present disclosure are not limited thereto. Forexample, the face stock may include multiple lanes of labels, e.g., 2lanes of labels. At the singulating station, each lane of labels may besingulated by a separate tool and applied to a separate line of products(e.g, each line of products is transported by a separate conveyingsystem), or a single tool may be utilized to singulate the multiple laneof labels and apply them to the same line of products (e.g, all of theproducts are transported by the same conveying system).

According to embodiments of the present disclosure, the labels arecoated with the adhesive as part of the same process in which they aredispensed and applied to products. This process is continuous and can bereadily incorporated into the existing (related art) dispensing schemes.In principle any adhesive that (a) can be coated at temperatures fromabout 60 to 170° C. and (b) requires either no further conditioning orvery small amounts of energy curing, can be utilized. These adhesivesmay be thermoplastic elastomer based or acrylic based adhesives orblends or hybrids of the two requiring no curing or self-curing, orwhich can be cured utilizing an external energy source such as UV. Thecoating temperature range may be wider but is limited by the ability ofthe coated substrate to withstand the temperature without distortion.

In one embodiment, adhesives that require energy activation to cure butmay be cured with very little energy to provide suitable adhesionperformance at very low coat weight may be utilized. In one embodiment,adhesives, which are formulated without any photo-initiators, thuslowering the cost, and are not cured after the coating, perform well ina range of applications.

According to an embodiment of the present disclosure, the adhesive isapplied, or the coating is applied which becomes an adhesive, in thesame continuous process, with a continuous web of label stock, in whichthe label is dispensed and applied to a substrate. Thus, at the labelingprocess (e.g., the point of dispensing), the label material (typicallyprinted) is unwound, moved through the coating head, cured if needed (oractivated), by a simple UV system, and then advanced to the singulatingstation where the web is separated into single labels (singulated),which are then applied to the product. A key requirement in this processis that, following the coating, the adhesive must be ready for usage ina short period of time (for example, in less than 10 seconds, or in lessthan 3 seconds) and requires little or no processing (curing) duringthis time so that the process remains compact and inexpensive tooperate.

In one embodiment, an adhesive of a relatively low molecular weight maybe selected, allowing it to be uniformly coated at a low coat weight.The adhesive may not require any curing, and can be utilized as a labeladhesive immediately. Unlike related art PSA labels, the adhesive coatedroll is not wound up (as the coated web is utilized immediately).Therefore, in the labeling process according to embodiments of thepresent disclosure, there are no issues associated with the related artlabel rolls where the adhesive has to be of sufficiently high molecularweight to resist the forces that the adhesive layer experiences in theroll form which causes it to flow and leads to edge ooze and blocking.To achieve the required molecular weights, related art processingdemands significant curing. In the process according to embodiments ofthe present disclosure, little or no curing is required. In oneembodiment, the labels have been perforated so singulation occurs byeffectively tearing the perforations at the dispensing point. However,singulation may occur by utilizing a variety of cutting methods at thedispensing point such as a laser or a flying knife (both with andwithout pre-perforations). Another label singulating method is to diecut or laser cut labels against a moving vacuum anvil (commonly a drum)which, after cutting, carries labels to the application point.

According to an embodiment of the present disclosure, an example labelmanufacturing process to provide a clear filmic label on a product maybegin at the manufacturing site by the printing of a roll of face stockmaterial (paper or film), as is done today with related art labeling,with information and advertising that will be placed on the products tobe labeled. During the same process (on the same site), but after theprinting, each label is weakened around its periphery by perforatingwith a rotating die. The roll of printed material, which carries theweakened labels, is then slit to provides a single lane of labels. Thisslit roll is then shipped off the manufacturing site and provided to theend user to be utilized at the client's site (i.e., the labeling site).

FIG. 7 is a schematic illustration of another labelling processaccording to an embodiment of the present disclosure. In FIG. 7, thesame reference numerals are utilized as in FIG. 1 to indicate similarprocess and materials, and the description thereof is not repeatedagain. Referring to FIG. 7, a roll of face stock 101 including aplurality of labels 101 a is unwound at unwinding station 110. The facestock 101 passes through a coating station 120 and an adhesive layer 103is coated on the face stock 101. The adhesive may be optionally cured atthe curing station 130. The web is pulled through the coating station120 by a driven roll or belt 136 at a transportation station 135 at aconstant speed. Where a belt 136 is utilized, the belt has a low surfaceenergy and is in contact with the adhesive. The web then passes throughan accumulator 138 which takes up any slack in the web resultingperturbations in the web speed downstream in the singluating anddispensing stations. The web may be optionally rotated 90° and reachesthe singluating station 140. After the individual label 107 issingulated (i.e., picked out of the web) and applied onto the product109, any left over matrix 111 is wound up at the winding station 160. Inother embodiments the belt 136 may be a friction belt which contacts theface stock 101.

While die coating and a continuous coating layer have been described inthe example process described above, embodiments of the presentdisclosure are not limited thereto. For example, spraying or screenprinting of the adhesive may be utilized, instead of the continuouscoating, for applications where the final appearance of the adhesive isnot important. In another embodiment, the adhesive may be patterncoated, utilizing a suitable coating die, for applications where thefinal appearance of the adhesive is not important. In both of thesecases the amount of adhesive required to produce a finished label isreduced. For example, the adhesive may cover about 30% to about 90% ofthe surface area of the label. Singluation may be affected by removing alabel from a pre-weakened web but can also be affected by cutting with alaser, a knife or a die. It should also be noted that where one or moretransportation stations (transportation systems) are utilizedimmediately after the coating station, the transportation system (e.g.,the belt) may be in contact with the web from either the adhesive sideor from the non-coated side opposite to the adhesive side.

According to another embodiment, a printed and slit roll of face stockmaterial provided to an end user is coated with an adhesive, cut orperforated in order to enable the singulation (separation of a singlelabel from the web) and applied to the products to be labeled in acontinuous fashion. The web may be perforated before the adhesivecoating and followed by adhesive coating, singulating and applying.During the singulating act, which may be conducted with a cutting die ora laser beam, the corners of the labels may be rounded to enhance theaesthetics of the label. When the web speed at either the singulation orapplication station is variable (i.e., the web is changing speed atdifferent stations) then an accumulator located after the coatingstation may be utilized to smooth out any variations in web speedarising from the either the singulating or application act, so as toensure that the coating speed is constant.

An indicia printing station in line on the web after unwinding and priorto the adhesive coating may be included in the labeling process. Inearly deployments, an end user may want the ability, for example, to addsome simple variable printing, such as a name or customized indicia, toeach label in addition to the earlier printing performed at themanufacturing site.

In one embodiment, the whole label may be printed in line with thecoating and singulating stations. This would allow the end-user tocreate labels from a starting web of material, either from a perforatedroll with weakened areas around the label area, or, where die cutting isdone fully at the singulating station, from a simple (e.g., blank) rollof film or paper. Printing fully in line may allow the end-user to fullycustomize every label and eliminate expensive inventory.

FIG. 8 is a schematic illustration of a process including the inlineprinting. Referring to FIG. 8, a roll of blank (i.e., non-printed) facestock 101 without any indicia printed thereon is unwound at theunwinding station 110, and pulled to a printing station 170 by thetransportation system 135. At the printing station 170, an ink layer117, representing an indicia, such as the information about the productand graphical presentation, is printed on the face stock 101, utilizing,for example, a high speed digital printer. The printed face stock isthen moved to the coating station 120, and optional curing station 130.The printed and coated web then advances to the singulating station 140,via an accumulator 138, before an individual label 107 is applied to theproduct 109. In one embodiment, the labeling process may further includea rotating anvil 119 where individual labels are cut out of the webutilizing a cutting die.

While the printing station 170 is illustrated in a process including acuring station 130 and a rotating anvil 119, embodiments of the presentdisclosure are not limited thereto, and various suitable combinations ofthe process stations may be utilized and some of the process stationsmay not be included, such as the curing station 130 and/or the rotatinganvil 119. Further, while the ink layer 117 and the adhesive layer 103have been shown to be on the same side of the face stock 101,embodiments of the present disclosure are not limited thereto, and theink layer 117 and the adhesive layer 103 may be positioned on oppositesides of the face stock 101. For example, the ink layer 117 may beapplied to the top surface of the face stock 101, and the adhesive layer103 may be applied to the bottom surface of the face stock 101.

FIG. 10 is a schematic illustration of a labeling process. Referring toFIG. 10, according to an embodiment, it takes less than 60 seconds foran individual label from the roll of face stock (e.g., a printed orunprinted roll of film or paper) to travel through the unwindingstation, the printing station (optional, may or may not be included),the coating station, the curing station (optional, may or may not beincluded), the accumulation station (optional, may or may not beincluded), the singulating station, and to the completion of theapplying of the label. In another embodiment, it takes less than 30seconds for an individual label from the roll of face stock (e.g., aprinted or unprinted roll of film or paper) to travel through theunwinding station to the completion of the applying of the label.

In a related art labeling process, a label includes a face stock, anadhesive layer under the face stock, a release system in contact withthe adhesive, and a liner under the release system. The face stock isprinted with an indicia (commonly describing and advertising the productto be labeled). This printing is typically done on a continuous(roll-to-roll) press producing many labels across and down the web ofthe label stock. The upper parts (face stock and adhesive layer) of thelabel-stock are then die-cut, to produce individual labels, which arestill carried in roll form and supported by the liner. Typically, butnot necessarily, the die-cutting is performed on the same asset as thatutilized to print the labels.

The printed die-cut label stock is then slit to provide a single lane oflabels and these slit rolls are then sent to an end-user who will putthe labels onto products via a dispensing process. Labeling occurs atthe end-user by feeding the die-cut label stock to a dispensing machinewherein labels are removed one-at-a-time from the liner and applied tothe products to be labeled. The release system allows theadhesive-backed labels to be removed easily from the liner. This istypically a continuous operation running at high speeds (30-600+labels/min) in which the to-be-labeled products are presentedcontinuously to the dispensing point where they are labeled.

The residual liner, coated with the release system, becomes a wastestream. This waste stream is collected on a rewind stand followingdispensing and may subsequently be land-filled or sold into low valuereprocessing.

The above related art process has existed for more than 50 years, andwhilst there has been continuous effort to improve this process (with,for example, the attempt to utilize thinner face and thinner linermaterials, and lower coat weights for the adhesive and release system,etc.) the basic construction has remained unchanged. Over this timeframe, the industry has developed enormous scale with the adhesivecoated often onto a wide web (often 2-3 meters in width) of releasecoated liner (film or paper) at very high speeds (often well in excessof 1000 m/min). The adhesive, coated on this release coated liner, islaminated to the face (film or paper) web in the same process, formingthe label stock. Most labels are manufactured this way through what iscommonly known as the transfer coating process. The adhesive can be alsodirectly coated on to the face material, followed by laminating with therelease coated liner, commonly known as the direct coating process. Formost of this time, the industry has sought to find ways to affectlabeling of PSA-type materials without utilizing a liner and theassociated release system, thus significantly improving material andsupply chain efficiencies, reducing cost and eliminating an increasinglyproblematic waste stream.

Typically, approaches to linerless solutions have fallen into one of twobroad categories: “Liner-free Labels” and “Activatable Labels”.

Liner-free Labels, while eliminating the liner, retain the releasesystem, and thus do not deliver the full cost potential of a truelinerless solution. This approach typically begins with the printing ofthe face stock and then applying a release system to the printed facestock before coating the reverse side with an adhesive to create aself-wound label stock that does not have the liner. Typically theself-wound stock is produced on a narrow web press utilizing anexpensive adhesive, often a UV-cured hot melt, at a speed considerablylower (<<1000 m/min) than that utilized in related art adhesive coating.The cost accumulation of lower scale, higher cost adhesive and thecontinued usage of a release system mean that a portion, and sometimesall, of the cost benefit relative to the traditional process, ofeliminating the liner is lost. It should be noted that the adhesiveneeds to have high enough modulus to reduce or prevent flow under thepressures it experiences in the roll as the label stock moves throughthe supply chain and the subsequent dispensing process. For this modulusto be attained, the adhesive needs to be cured (i.e crosslinked). If theadhesive is not cured it will flow under the roll pressure, leading toboth contamination on the edges of the labels (due to edge ooze),affecting the aesthetics, as well as issues with unwinding of the rollat high speeds (during dispensing), since this ooze tends to make theroll blocky. This need for higher crosslinking (via curing) necessitatesthe usage of higher adhesive coat weights to get the required tack andadhesion to the target surfaces, and thereby drives the cost up further.

A further challenge facing this approach is to create individual labelsfrom the label stock (throughout this description, also referred to as“singulation”) at the point of dispensing by the end-user. Since thereis no liner to carry the pre-die cut labels to the dispensing point,singulation can only occur at the point of dispensing. One approach tothis challenge is to utilize a re-usable liner at the dispensing point.This allows a label to be die cut from and the web, singulated, and tosubsequently be carried to the dispensing head by the temporary liner.The re-usable liner reduces the cost benefit of the solution (since aliner is re-introduced) and adds complexity to the process. Anotherapproach to solving the dispensing problem of a liner-free adhesivesystem utilizes labels that are ‘weakened’ within the web prior todispensing. In this scheme, the surrounds of labels within the web areweakened by slits or perforations. This ‘weakening’ is typically done onthe printing press (and would replace traditional die-cutting) so thatthe weakened self-wound material can be provided to the end-user in aready to use state. The line of weakening for each label includes atleast one aperture which provides for engagement by a tool, which at thetime of dispensing can be utilized to break the weakened area and thusseparate the leading label in the web and allow it to be applied to aproduct. In this scheme, the self-wound web carries the label to thedispensing point but labels are easily removed from the web. Whilst suchschemes solve the dispensing challenge, they have seen limited adoptionbecause the limited cost benefit of the total solution does not justifythe additional complexity of dispensing.

Activatable Labels involve applying a specialty coating or cover layerto the adhesive system (essentially replacing the liner and the releasesystem) or having an adhesive system which is non-tacky at roomtemperature. In these solutions a separate process, just prior tolabeling, either removes the coating/cover layer to ‘unmask’ theadhesive or activates the adhesives through an external stimulus such asheat or liquid. Activatable labels are supplied to the end user in anon-tacky state, and then the labels are activated, i.e., the label'sadhesive is exposed (activated) to its tacky state just prior toapplication to the intended product. Obviously activatable labels areprinted prior to activation. Well described schemes include the use ofultraviolet (“UV”) energy to heat the adhesive, corona treatment toactivate the surface, radiant heat to warm the adhesive, moisture toactivate a rewettable adhesive, microencapsulating an activatormaterial, which can then be crushed to allow the activator to mix withthe rest of the formulation and activate the adhesive, overcoating theadhesive with a de-tackifier layer, which is later removed by heat ormechanical means, and ultrasound energy to activate the adhesive.

By far, the most common activation scheme utilizes heat activation,involving such schemes as the removal of a protective coating oractivating of the label adhesive utilizing heat. For heat activating theadhesive, various techniques have been proposed. The adhesive remainstacky for a short time defined as the open time of between 0.2 and 10seconds within which the adhesive has to be applied to the substrate. Inaddition, general methods for heating utilizing radio frequency (“RF”)energy, inductive heat, radiant heat, and visible light also are wellknown and could be applied to this list of activation methods. Thesetechniques may have some utility for low-speed operations, but asapplication speeds increase for high speed labeling, these methods allsuffer in that the exposure times of the labels to the heating elementsmust somehow be increased in order to gain sufficient heating. The size,and the concurrent cost, of the units capable of supplying sufficientheating has thwarted high-speed applications.

While all of the above related art activatable label schemes do indeedeliminate the liner and the release system, and, therefore, a wastestream, they replace them with another, often relatively expensivematerial, add complexity and again do not meaningfully improve cost. Thecost issues arise both from the use of often expensive components in aspecialty coating which masks the adhesive or expensiveadditives/process to create a non-tacky adhesive. Further therequirement for additional process assets to remove the coating oractivate the adhesive also adds cost to the overall solution. Finally,singulating the labels at the point of dispensing remains challenging(without a carrier web as described previously). As discussed, relatedart approaches to singulating at the dispensing point exist but addcomplexity and the cost of proposed activatable label solutions do notjustify end-users engaging in this additional complexity.

Finally, it should be noted that due to the often complex formulationsneeded to render an activatable adhesive non-tacky the final adhesiveafter activation is commonly hazy. If the adhesive is hazy then ameaningful part of the label market, the so-called ‘clear-on-clear’label, cannot be addressed. For clear-on-clear a clear printed film witha clear adhesive is applied to a product and only the print is evidentallowing a consumer to see product beneath the label. If the adhesive ishazy then the appearance is unacceptable.

The labeling process according to embodiments of the present disclosureoffers a number of enhancements over related art PSA labeling. First, iteliminates the need for a liner and release system. This has significantcost and environmental benefits. Unlike other approaches, the eliminatedmaterials are not replaced with another material. The usage of a hotmelt or warm melt adhesive, e.g., at low coat weights, provides materialcost savings whilst offering the desired adhesive performance. A smalladhesive coating unit (e.g., for coating on a web including only asingle pane of labels, in contrast to coating on a wide web includingmultiple panes of labels) is included in the labeling system (i.e., thenovel coating and dispensing system). The cost of the coating unit willbe amortized over many years of running and many thousands of labels anddoes not materially add to the total cost of the solution. In addition,this coating unit replaces the large coating asset utilized in thetraditional PSA labeling process.

The labeling process and system according to embodiments of the presentdisclosure also offer the ability to dramatically simplify the supplychain. In deployments where the printing is done at a separate site fromthe end-user, the need for an adhesive coater and a liner manufacturerare eliminated (essentially taking two steps out of the value chain). Indeployments where the printing is done fully by the end-user in-linewith the dispensing, the printer is removed from the supply chain. Theseimprovements offer efficiency and cost benefits and, additionally, offerthe end-user tremendous flexibility in their supply chain and theability to customize their labels.

Another approach to high speed labeling, but not utilizing a PSA, is asystem called “Cut and Stack”. This labeling system is primarily forpaper labels and involves the following typical steps: first, the paperface stock is printed with labels, typically on a roll-to-roll press.The labels are die cut from the printed face stock and stacked in amagazine. It should be noted that the shapes of labels are typicallyconfined to square or rectangular shapes. Typically this die cutting andstacking occurs at the end of the printing press. The stacked labels arethen delivered to an end-user who loads the magazine of labels into afeed system from which individual labels are taken and wiped with awater based glue. The glue wiped labels are then transported to adispensing point where they are applied to products.

The cut and stack process is commonly utilized in high volumeapplications and provides an inexpensive form of paper labeling. Howeverthe system is only useful for paper labels. For filmic labels, thequality is not sufficient, especially when a clear label appearance isneeded, i.e., clear-on-clear applications. Further, it is difficult toeffectively dry the water based adhesive with a filmic face stock.

The labeling system according to embodiments of the present disclosureoffers a cost-effective alternative to cut and stack, and enables theusage of filmic face stock. Similar to cut and stack, the labelingsystem according to embodiments of the present disclosure utilizes onlya printed face stock and an adhesive. However, the system accordingembodiments of the present disclosure utilizes a high performance, clearand non-aqueous based adhesive (which requires no drying). Such adhesiveis suitable to label both paper and filmic face materials, and providesa much high quality final appearance. The warm/hot melt adhesive alsoprovides water resistance, water whitening resistance and water bathimmersion resistance, which is essential for clear labels on bottlessubmerged in ice chests.

According to an embodiment of the present disclosure, a pressuresensitive adhesive label consists of a face stock; an indicia on theface stock; and a pressure sensitive adhesive on the face stock, whereinthe pressure sensitive adhesive has a coat weight of about 3 gsm toabout 20 gsm, and a 180° peel of about 1 N/inch to about 20 N/inch.

The following Tables and Examples illustrate the performance of theadhesive on various surfaces.

EXAMPLE 1

A hot melt adhesive from BASF, acResin® A250 UV was coated onto arelease liner utilizing a slot die and UV cured at 0, 15 and 30 mJ/cm².After curing, it was laminated to either a 1 or 2 mil polyester film inorder to test adhesion to glass, HDPE and stainless steel (SS) panels.The adhesive on the 1 or 2 mil PET film was laminated to the respectivepanel, rolled up and down with a 2 kg rubber roller and allowed to dwellon the panel for various periods of time listed in Table 1. The 180°Peel adhesion was measured utilizing a LabThink XLB(B) Auto TensileTester (LabThink Instruments Co. Ltd.) at a speed of 300 mm/min and peelvalues reported were from an average of 3 to 5 measurements.

EXAMPLE 2

A sample was prepared substantially similar to the samples of Example 1,except that a Henkel UV curable adhesive UV 5321 was utilized instead ofthe acResin® A250 UV. The test data is shown in Table 2.

TABLE 1 Glass panel, HDPE panel, SS panel, 180° Peel, 180° Peel, 180°Peel, Coat UV N/inch N/inch N/inch weight, Dosage, 30 24 7 38 30 19 3021 Example Adhesive gsm mJ/cm2 Film min hr days days min days min days1.0 BASF acResin 10 15 1 mil 6.1 8.8 10.6 4.5 4.42 10 10.94 A250 PET 1.1BASF acResin 10 30 1 mil 6.3 11.6 10.4 3.9 5.7 4.6 9 A250 PET 1.2 BASFacResin 10 30 1 mil 7.5 9.4 11.2 3.1 4.1 7.6 11.1 A250/Foral PET 85E*,90/10 1.3 BASF acResin 9.8 0 2 mil 15.7 A250 PET 1.4 BASF acResin 9.8 152 mil 4 9.1 A250 PET 1.5 BASF acResin 9.8 30 2 mil 10 15.3 A250 PET 1.6BASF acResin 13.6 0 2 mil 14 A250 PET 1.6 BASF acResin 13.6 15 2 mil 1317 A250 PET 1.7 BASF acResin 13.6 30 2 mil 9.6 15.9 A250 PET

Foral 85E* is from Eastman and is utilized as a tackfier.

TABLE 2 Glass, 180° Peel, Adhesive UV N/inch Thickness, dosage, 30 24 30Example Adhesive mil mJ/cm2 min hours days 2.1 Henkel UV 0.65 0 9.5 11.59.8 5321 2.2 Henkel UV 0.65 6 2.8 8.54 8.2 5321

A truly linerless labeling process and system which eliminate both theliner and the release system have been described. The labeling processapplies the pressure sensitive adhesive in-line with the dispensing ofthe labels. Further, the printing of the label graphics, in whole or inpart, may be performed on the label stock in-line with the dispensing. Ahot melt or warm melt adhesive or UV curable syrup (or other suitableenergy-activated adhesive) is coated to a label face stock, andoptionally rapidly cured before dispensing singulated labels onto theproducts (such as bottles or containers) in a single continuous processto achieve a low cost waste free system. The system eliminates both theliner and the release system, and offers significant supply chainbenefits (as labels are created at point of use). The inventionsdescribed herein offer meaningful reductions in the amount of adhesiverequired (reducing the adhesive in some cases by more then 50%). Furtherthe inventions allow also for meaningful reductions in the thickness ofthe face material. In addition, each material layer utilized in thelabel manufacturing and application process remain on the finallyapplied label, and no additional layers, which requires removal upondispensing of the label (such as the liner and/or the release system),are ever present in the label and the process of manufacturing orapplication of the label. Taken altogether the invention results in adramatic reduction on overall material usage and the consequentenvironmental footprint of PSA labeling.

While one or more embodiments of the present invention have beendescribed with reference to the figures, it will be understood by thoseof ordinary skill in the art that various changes in form and detailsmay be made therein without departing from the spirit and scope of thepresent invention as defined by the following claims, and equivalentsthereof.

1. A method of labeling a plurality of products, the method comprising:unwinding at least a roll of face stock, the roll of face stockcomprising a perforated line or a weakened line configured to convertthe roll of face stock to a plurality of individual labels aligned in asingle lane; coating a pressure sensitive adhesive to the roll of facestock with a coat weight of about 3 gsm to about 20 gsm; singulating anindividual label from the roll of face stock at the perforated line orthe weakened line; applying the individual label to a product of theplurality of products; wherein (a) the coating, singulating and applyingare conducted sequentially in a single continuous operation on the rollof face stock, and (b) a release layer and a liner are not used in themethod.
 2. The method of claim 1, further comprising printing an indiciaon the face stock.
 3. The method of claim 1, wherein the printing isconducted prior to the coating of the pressure sensitive adhesive at asame site as a site for the coating of the pressure sensitive adhesive.4. The method of claim 1, wherein a total time needed from unwinding asection of the face stock corresponding to an individual label to acompletion of the applying of the individual label is about 60 secondsor less.
 5. The method of claim 1, wherein the coating is conducted at atemperature of about 60° C. to about 170° C.
 6. The method of claim 1,wherein the applying of the individual label is about 10 seconds or lessafter the coating of the pressure sensitive adhesive.
 7. The method ofclaim 1, wherein the roll of face stock comprises a pre-printed facestock.
 8. The method of claim 1, wherein the pressure-sensitive adhesiveis a warm melt or a hot melt pressure-sensitive adhesive.
 9. The methodof claim 1, wherein the pressure-sensitive adhesive is an acrylicpressure sensitive adhesive comprising tackifier.
 10. The method ofclaim 1, wherein the pressure-sensitive adhesive is selected from agroup consisting of acrylic polymers, polyurethanes, silicone polymers,copolymers of styrene and butadiene, styrene and isoprene, styrene andethylene butylene and combinations thereof, with and without additives.11. The method of claim 1, wherein coating the pressure sensitiveadhesive to the roll of face stock comprises coating on the face stockin a shape of strips with each strip spaced apart from neighboringstrips.
 12. The method of claim 1, wherein coating the pressuresensitive adhesive to the roll of face stock comprises using diecoating, screen coating, or spray coating.
 13. The method of claim 1,further comprising multiple lanes of labels.
 14. The method of claim 13,wherein each lane of labels is singulated by a different tool and thelabels therefrom are applied to different lines of products.
 15. Asystem for labeling a plurality of products, comprising: an unwindingstation including at least a roll of face stock, the roll of face stockcomprising a perforated line or a weakened line configured to convertthe roll of face stock to a plurality of individual labels, theunwinding station configured to unwind the roll of face stock; a coatingstation to coat a pressure sensitive adhesive to the roll of face stock,the coated roll of face stock not including a release layer and a liner;a singulating station to singulate an individual label from the roll offace stock at the perforated line or the weakened line, the singulatingstation comprising a single tool or multiple tools to singulate thelabels; and a dispensing station to apply the individual label to aproduct of the plurality of products; wherein the coating station, thesingulating station and dispensing station are located at a same site toprovide sequential coating of the pressure sensitive adhesive,singulating of the individual label and applying of the individuallabel.
 16. The system of claim 15, further comprising a transportationstation to move the face stock from an unwinding station to the coatingstation, the singulating station and the dispensing stationsequentially.
 17. The system of claim 16, wherein the transportationstation comprises at least a belt.
 18. The system of claim 15, furthercomprising an accumulation station between the coating station and thesingulating station to accumulate the face stock when a speed of theface stock at the coating station is faster than a speed of the facestock at the singulating station.
 19. The system of claim 15, furthercomprising a printing station to print an indicia on the face stock. 20.The system of claim 15, wherein the roll of face stock comprises apre-printed face stock.
 21. The system of claim 15, wherein thepressure-sensitive adhesive is a warm melt or a hot meltpressure-sensitive adhesive.
 22. The system of claim 15, wherein thepressure-sensitive adhesive is an acrylic pressure sensitive adhesivecomprising tackifier.
 23. The system of claim 15, wherein thepressure-sensitive adhesive is selected from a group consisting ofacrylic polymers, polyurethanes, silicone polymers, copolymers ofstyrene and butadiene, styrene and isoprene, styrene and ethylenebutylene and combinations thereof, with and without additives.
 24. Thesystem of claim 15, wherein the coating station coats the pressuresensitive adhesive on the face stock in a shape of strips with eachstrip spaced apart from neighboring strips.
 25. The system of claim 15,wherein the plurality of individual labels are aligned in multiplelanes, each lane of labels is singulated by a different tool and thelabels therefrom are applied to different lines of products.